Welcome back. And what a great session this was this morning. You know, the bar keeps getting continually raised in this meeting. And this next session which is our mid morning session. It's my pleasure to introduce Dr. Adam shields our next speaker. Dr. Shields is joined Rockford gastroenterology associates in 2004, and now serves as a managing partner there, and a practicing gastroenterologist he also has a clinical associate professor faculty position at the University of Illinois College of Aaron specializes in ability disease and pancreatic disease, and he serves on the reimbursement committee for the SGP, and has previously served on the SG health and public policy committee so Aaron Welcome, thanks for doing this. The floor is yours. So the topic of this discussion will be basically imaging and gastroenterology. I'm going to talk a little bit about some specific tests or clinical significance and the impact on management. And, you know, gastroenterology is a very visual field whether it's doing endoscopy or interpreting imaging studies. One of the things that I always emphasize to my apps is, is the importance of kind of being an amateur radiologist, sort of like we need to be an amateur hematologist to interpret some of the anemia referrals we get being an amateur radiologist is is very And in fact, my nurse practitioners are aware that when we're talking about a case they they should probably have the imaging studies pulled up and ready to go because we like to do a lot of review and try to learn something and oftentimes it does have an impact on the management of the case. So my objectives here are to review some common GI imaging studies. And then I'm going to spend most of the time just reviewing some clinical scenarios along with some, some images that that might change management, and hopefully along the way. And if you're not familiar with some of the different imaging studies that we're going to look at maybe you can learn a little something so that the next time you have a case to look at you'll you'll have a little better knowledge of, of what it is that that you're actually looking at. So, the, the number of studies imaging studies that gastroenterologists uses is fairly long. And again, we're not expected to become expert in any of these but especially the ones that you might order more frequently, having some familiarity with both how the test is done but also also with the interpretation can be can be very helpful. And we're going to during my examples we're going to we're going to look at quite a few of these but I'll just kind of go through and highlight some of the pluses and minuses of the different tests. So ultrasound, obviously is a very common imaging study that we use to assess gastrointestinal diseases. It has the advantage of being relatively inexpensive there's minimal discomfort to the patient can be done in a variety of settings, settings, including emergency department physicians offices or, or the radiology department. It is particularly useful for evaluating disorders of the gallbladder and liver can also be used to image the pancreas and assess the mesenteric vasculature classic x ray so these are the things that we would typically think of as plain films are also and can be used for evaluating disorders of dysphagia after we based based on the discussion that we just had, you can see how these can be useful for assessing issues with swallowing. And those include tests like video swallow esophagram or upper GI series, the small ball follow through barium animals are playing films all of these are what we consider a kind of, you know, just regular type of x rays interpretation of CT is one of the more challenging ones but it is, since it's one of the more common tests that we order having some knowledge of the test is useful. Obviously the cost is higher and there are radiation exposure risks associated with both x ray and with CT but there's a number of different that will come up in GI, including just routine imaging of the chest abdomen pelvis triple phase liver CT pancreatic protocol CT CT and choreography CT calligraphy or even CT and geography MRI doesn't carry the radiation risk that's associated with plain x rays and CT but it does come with a very high cost. And, of course, there are many patients who are either unwilling to have MRIs because of claustrophobia or unable to because of prior implantation of devices such as pacemakers and defibrillators, but MRI can be particularly useful for disorders of the liver, pancreas, pelvis and MRCP nuclear imaging, sometimes affectionately referred to as unclear imaging and does have a role. We're going to talk about that during a couple specific examples here involves typically an injection of a radio tracer and then monitoring that with with specific gamma ray counters in the radiology department. And of course during procedures themselves we end up having imaging as well so you know being able to interpret imaging studies is critical to performance of some of these procedures, specifically er CP but also placement of various types of stance stricture dilation, or pseudocyst drainage so just kind of a general overview of the the type of tests that that are involved. There are. This is by no means a comprehensive list. But there are a number of clinical scenarios in which imaging can clearly have an impact on management. And so being able to understand the, you know, the, the role of the different studies and how to interpret them can be very helpful. And we're going to go through each one of these in in some detail. But they include things like dysphagia abdominal pain, especially if it's located in either the epigastrium or the or the right lower quadrant patients who present with jaundiced special suspected by leak obscure GI bleeding, or the evaluation of the liver lesion. So with the rest of the discussion I'm going to just kind of present some general clinical scenarios and then we'll look at some primary imaging studies and see how these can help to with management decisions. So, obviously, you just got a very in depth discussion regarding the evaluation of dysphagia so I'm not going to go into nearly that degree of detail, but typically when patients show up with for the evaluation of dysphagia. The very first question is, is whether this is oral pharyngeal dysphagia, or whether it's esophageal type dysphagia and I've already had a good description of what the difference between those two is. But a video swallow is very useful for the patient, for example, who presents with perhaps difficulty initiating a swallow or develops coughing episodes while swallowing, raising the suspicion that there may be some element of aspiration and the video swallow, especially if interpreted by a skilled speech pathologist is really the most important test. So you can see in this in this case here the patient has has swallowed a bolus of this looks like fairly thin barium and you can see that this is the hypopharynx here, and with a normal swallow you would see contrast going down into the esophagus, but unfortunately in this patient's situation. There's also contrast going down into the trachea. And so this would be a very classic image of a patient who has oral pharyngeal dysphagia, causing aspiration, and of course this would have major aspiration. And of course this would have major implications for for management of the patient. Oftentimes, this is the study that is done right before we're asked to place a feeding tube on a patient and if the speech pathologist interprets this and says that, you know, there's clear evidence of penetration or aspiration that this is a patient that we would oftentimes proceed with placement of a feeding tube. Occasionally patients will present with symptoms that are suggestive of a Zanker's diverticulum and oftentimes they'll describe dysphagia, difficulty initiating a swallow, but they might have additional symptoms such as regurgitation of food especially. Patients may talk about finding food or liquid on the pillow at night, or they may present with recurrent aspiration pneumonia as the food sits in the Zanker's and then it's easily aspirated. So the best test for doing that is a contrast study of the esophagus. You can see on the left here exactly where a Zanker's diverticulum arises. It arises from just above the cricopharyngeus and some of these sacs or diverticulum can be quite large. And a lateral film is the best way to visualize this. And so again, here's a patient who has swallowed barium. Some of it has made its way past the upper esophageal sphincter down into the esophagus, but you can see there's a significant portion that has settled within this within this diverticulum. Obviously, this would be a very useful finding. This patient can then be managed with either endoscopic or surgical management of a Zanker's diverticulum. Occasionally, a patient will present with symptoms that are suggestive of achalasia. So for example, the patient who has perhaps longer standing dysphagia for both liquids and solids, sometimes regurgitation. And sometimes we opt to go with a barium esophagram first in this situation for endoscopy just because we might be concerned about a lot of food and liquid being retained in the esophagus. And there's some risk with doing endoscopy in that situation. But this looks similar to the slide that you had seen in the last presentation, but you can see a quite dilated esophagus with a column of barium. And then it tapers down into this kind of classic bird beak, which is the hypertensive lower esophageal sphincter. We typically don't rely on this as a definitive answer for the diagnosis of achalasia. That's made using esophageal manometry. But anybody with a barium x-ray like this, there would be a high suspicion that you were dealing with achalasia. So that's how some of the ways which imaging can be useful for evaluation of dysphagia. Now we're going to move into a couple of areas in the abdomen where imaging can be helpful. So epigastric pain, obviously a very common problem seen both in the inpatient and the outpatient setting in gastroenterology. And, you know, the differential diagnosis is fairly long, but one of the things that is pretty high on the list of possibilities is symptomatic gallbladder disease. And in that situation, clearly the most useful test is a transabdominal ultrasound. It has very high sensitivity for detection of gallbladder stones. So in this case, this is a transabdominal ultrasound. Again, ultrasound interpretation can be a little bit challenging, especially for patients that have a larger body habitus because the images may not be that clear. But this would be kind of a typical image here. And, you know, fortunately, in this case, the radiologist has done us a favor and drawn an arrow towards the obvious abnormality. But this is something I think we would all be able to recognize, even if they hadn't pointed this out. But what you see here is you can see the probe is on the abdominal wall here. This is some subcutaneous fat tissue. And then this is a pretty clear outline of the gallbladder. The gallbladder itself has no significant gallbladder wall thickening. But there's obviously a very good sized stone here within the lumen of the gallbladder. You can tell that something is a stone as opposed to, for example, a polyp or a mass based on two characteristics. One is it's bright on the surface, so it's echogenic. And two, it has posterior acoustic shadowing, so it casts a shadow because all the ultrasound waves are pretty effectively reflected. So this is a good example of one kind of larger stone. Here's a patient who has multiple smaller stones. But again, it kind of has the same feature with very bright on the surface and there's this nice acoustic shadow afterwards. So again, if you send a patient for this test and you want to know how things look, pulling up the images can be very, very useful. Another imaging test commonly used to evaluate patients with epigastric pain would be an abdominal CT. And again, interpretation of CT, it does take a little bit of practice. But if you're reading through the reports and looking at the images yourself, oftentimes it's not too difficult to correlate what the radiologist is seeing with what you're seeing. So for those of you who haven't reviewed CTs in much detail, I'm just going to give you a very brief introduction to what we're seeing here. So this is what's called an axial image. So this is kind of a transverse slicing the patient like a bunch of slices of bread. And what we're seeing here is this is a normal appearing liver here. This is spleen over here. There's the left kidney, right kidney that happens to be a cyst in this kidney. And then you can see a little bit of what looks to be kind of healthy looking pancreas here. But then right in the middle is obviously a very abnormal, large fluid collection within the pancreatic bed. And this would be kind of a classic finding for perhaps a developing pseudocyst. And then you see another, this is the same patient, just another slice where you can see that there's just a lot of additional fluid around the pancreas, within the pancreas. There may even be a couple of areas of necrosis. So for patients with suspected pancreatitis or complicated pancreatitis, abdominal CT can be an invaluable study. Of note, despite what a lot of times happens coming to the emergency department, not all patients with an abdominal CT, I'm sorry, with pancreatitis need an abdominal CT. Typically, it's reserved for patients who have a complicated course where you're trying to assess for the presence of various complications. Here's another example where an abdominal CT was very helpful. So on the left, again, this is an axial view. So the transverse view. This is what's called a coronal view. So it's kind of slicing the patient from head to toe. And in this case, this is a patient who might have come in with vomiting and CT shows a gastric volvulus. And I think the coronal image here probably shows things better. You can see there's two large fluid-filled structures in the upper part of the abdomen. And it turns out that this is the fundus and this is the antrum here. Obviously, that's not the typical configuration. And so this is a stomach that has kind of flipped on itself and formed a volvulus. And you can diagnose volvulus with endoscopy, but it's much better characterized by doing some type of an imaging study. And CT is very useful in this situation. Again, evaluation of the pancreas can be very well done with abdominal CT. So if you have a patient where you suspect chronic pancreatitis, perhaps they've had abdominal pain and weight loss or steatorrhea, the presence of multiple calcifications. And again, there's a nice arrow pointing towards this is where the pancreas is right here. Multiple calcifications within the pancreas is pretty much diagnostic of chronic pancreatitis. And as alluded to in an earlier lecture, diagnosis of chronic pancreatitis can be somewhat challenging based on the difficulty with some of the other tests. But if you have this finding, you can be pretty confident that you've got the correct diagnosis. One other study that can be useful for the evaluation of epigastric pain, and this might be useful for somebody who complains of postprandial abdominal pain, would be to perform a Doppler ultrasound of the mesenteric vessels. And basically what you're seeing here is the ultrasound probe has identified one of the major blood vessels. This happens to be the superior mesenteric artery. And it's measuring flow. And that's what these are waves here, corresponding with the systolic and the diastolic portions. And based on this, you can calculate a speed measurement, which gives you an idea whether there's a significant stenosis of one of the major blood vessels supplying the gut. So those are some good examples on how imaging studies can be helpful for the evaluation of epigastric pain. The other part of the abdomen where imaging can be helpful is the right lower quadrant. Patients who come in with, for example, symptoms of acute appendicitis with right lower quadrant pain, this is really the procedure of choice for making the correct diagnosis. And what you see in this image here, again, the arrow points nicely to this dilated appendix with some surrounding inflammatory changes. And this is a patient who actually has a perforation of the appendix. There's some periappendiceal fluid and inflammatory changes that have gone on. So patients with suspected appendicitis, this is really the test of choice. Some other diagnoses that can be made by CT would be intestinal angioedema, not a particularly common one, although I think there are probably patients that have this that we don't necessarily think about or make the diagnosis. But again, this is an axial CT scan. And what you're seeing here is this is what normal small bowel looks like. And the thing to point out here is that the wall of the small intestine is very thin. You can almost not see it. But then when you look over here, this is in the right lower quadrant, you can see there's a lot of edema and thickness to the, this is probably part of the ileum here. And this would be kind of a classic appearance for a patient who has intestinal angioedema, perhaps from hereditary angioedema or even use of an ACE inhibitor. Obviously, one of the more common conditions that we manage is inflammatory bowel disease. You know, Crohn's can be a challenging diagnosis to make because of the location of disease. If it's involving the small intestine, obviously reaching it endoscopically isn't always possible. But sometimes image parts of the small bowel can be imaged well enough to, you know, raise suspicion for Crohn's disease. Again, this is another axial cut to the CT. Here's kind of normal looking intestine here. But you can see again, here is a very abnormal looking part of the terminal ileum as it's entering into the cecum. There's thickening and edema, inflammation of the terminal ileum. Obviously, this would be a very classic finding for somebody with Crohn's disease. Moving on to another area where imaging can be very helpful is the patient with jaundice. You know, typically these are the patients that come in and the very first question that we want to answer is, is this an obstructive jaundice or is this some type of a intra-hepatocellular process? And so abdominal ultrasound is probably the most appropriate option for this patient. In this case, for example, an ultrasound was done. So just to kind of orient you here, this is gallbladder right here. And here is the outline of the liver. And you can see everything looks pretty normal over here. But then when you come down to this area, there's actually an intra-hepatic stone. And there's a lot of blood in this area. And there's a lot of blood But then when you come down to this area, there's actually an intra-hepatic stone. And there's marked dilation of the intra-hepatic bile ducts. And so ultrasound has the, not only is it good for evaluating the gallbladder, but it's very good for assessing for the presence of both intra-hepatic and extra-hepatic bile duct dilation. So very good initial study for the patient who presents with jaundice. CT can be also helpful for the patient with jaundice, especially if you've already determined that there's some type of an obstructive process. CT can be helpful for assessing the etiology of the obstruction. And in this case, what you can see, the notable features are, here's a fairly normal looking liver. This gallbladder is actually quite distended, dilated. And then there's, this is actually common bile duct, which is dilated and the pancreatic duct, which is also dilated. And then there's a large mass here arising from the pancreas. So this would be kind of a classic CT scan for a patient with an obstructing pancreatic cancer causing malignant obstruction of the bile duct. And so this would be a helpful test. Of course, other ways to image the bile duct for a patient who's jaundiced would be to perform an MRCP. And as we talked about during the EUS ERCP talk yesterday, MRCP has essentially replaced diagnostic ERCP, kind of as the test of choice for patients with suspected bile duct problems. And so this, you can see very, very nice images. This is the bile duct here. These are the intrapadic bile ducts, which are somewhat dilated. And then it's very easy to see there's at least three and maybe another stone down at the bottom here causing obstruction of the bile duct. And you could feel very confident taking this patient to ERCP after having this finding because you'd be certain that you would be able to remove those stones and have a good indication for actually performing the procedure. I know that MRIs can be a bit intimidating to read because oftentimes the studies are quite large. There may be 20 or 25 different imaging sequences. But if you look through them and you find the ones that specifically identify the bile duct, they're actually fairly easy to interpret, especially if you're comfortable with looking at ERCP images. The images are almost identical. And it's really a very useful study. This is probably one of the tests that I review the most with my nurse practitioners to make sure that they really can understand how to interpret these. And of course, ERCP, I won't belabor this too much because we covered this yesterday, but this would be a typical image of a patient. Here's the scope. You can see if you look very carefully, there's a thin wire that's gone up into the biliary system. The bile duct and the intrapadic ducts are very dilated. And then what you see here is there's an area where you don't see any contrast. And this would be a classic stricture, for example, for somebody with pancreatic cancer causing a malignant biliary obstruction. One of the other places where imaging can be very helpful is with the patient with the suspected bile leak, most commonly after a cholecystectomy. The patient oftentimes will come in because of abdominal pain within the first week after a cholecystectomy. And abdominal CT is often the first thing ordered. And in this case, what you see is, again, here's the liver here. And you can see surrounding the liver is a very large fluid collection. Now, this isn't diagnostic of suspected bile leak, but it would raise concern that that's what you're dealing with. I'm going to talk just a little bit about HIDA scans, because I think they are probably one of the more perhaps misused studies. But I think knowing how a HIDA scan works will help you determine whether it's a test that you actually need to perform. So just very briefly, a HIDA scan, also called cholecystectomy, is a test where a radio tracer, usually technetium-99 labeled immunodiacetic acid, that's where the IDA part comes from, in case you were wondering, is injected into the venous system. It's then actively taken up into the liver and then secreted into the bile duct. And then images are taken using a gamma nuclear scan over about 60 minutes. And the best way to remember what a HIDA scan does is it tells you where the bile is going to flow. So the tracer goes wherever the bile flows. So for example, in this case, you can see in the early images, as the tracer is being taken up into the liver, you can see the outline of the liver a little more here. Now you're starting to see a little bit of secretion into the bile duct. But in this case, bile is accumulating where it's not supposed to. It's filling the gallbladder fossa after a cholecystectomy. And so this would be a positive study telling you that the patient actually has a bile leak. I can tell you that there are a lot of indications that have been given for HIDA scan. In my experience, the only two really useful indications for a HIDA scan are somebody with a suspected bile leak or somebody with suspected acute cholecystitis. It oftentimes is ordered for patients with chronic abdominal pain, chronic right upper quadrant pain. And I can tell you, with very few exceptions, it doesn't help anything. It doesn't add anything to the actual management of the case. In fact, oftentimes it leads to an unnecessary cholecystectomy. So be careful about ordering HIDA scans. Try to limit them to situations where you really think it's going to affect management. For somebody who has a suspected bile leak, typically the next procedure would be to perform an ERCP. And here you see a couple of nice images of what that would look like. So again, the scope is here. A contract has been injected into the bile duct. And then in this case, it's leaking out. Right here, it's leaking out the cystic duct. So about 80% of post-cholecystectomy bile duct leaks come from the cystic duct. And this is a kind of a more interesting one. Again, contrast has been injected into the biliary system, but you don't see anything near where the cystic duct should be. Cystic duct should be around here somewhere. Instead, what you see is the contrast leaks out one of the intrahepatic branches off the right hepatic duct. And this is what's called a duct of Luschka leak. It accounts for about 20% of post-cholecystectomy bile leaks. It's always kind of interesting when you find one of these. And the good thing about ERCP is not only can you localize the leak, but typically it closes very easily after stent placement. Just a few more images to go over here. Obscure GI bleeding is a situation where sometimes our scopes aren't able to localize or address the bleeding site. And so a nuclear bleeding scan is sometimes used. And again, just to briefly review how this is done, you take the patient's red cells labeled with technetium, you inject it back into the patient, and then you scan them over about 60 minutes and look for areas where there's abnormal tracer accumulation. So you can see each one of these is taken about every five minutes. And as we go along, we see that there's an area that's lighting up here, probably somewhere in the small intestine. And that would help give you some localization for where the actual bleeding site is. We are doing more CT angiography now for patients. Although the thing to remember about this is the patient has to be actively bleeding right at the time that the contrast is injected for it to be a positive study. But in this case, you can see there's a contrast which has extravasated into the bivalumen. The last area where I think imaging can be very useful is a patient with a liver lesion. Again, ultrasound is oftentimes a good starting point. And you can see here that there's a fairly large well-circumscribed lesion within the liver that would be, for example, in a cirrhotic concerning for development of hepatocellular carcinoma. Triple-phase CT can be helpful. This is a classic what a hepatic hemangioma looks like, where on initial imaging, you can see this kind of well-circumscribed area here. It's hypodense. But then as you take more delayed images, you start to see it fill in with contrast. And by the time you get to the very late images, it's almost completely filled in. And when you see this, you can be pretty confident that you're dealing with a hemangioma. And finally, MRI can be helpful. This would be a good example of somebody with what's called focal nodular hyperplasia. So again, you see the liver outline here, and then you see this very well-circumscribed mass with what's typically referred to as a central scar. And this would be a classic finding for focal nodular hyperplasia. So I think with that, I'd like to end with just a couple of quick polling questions. So imaging studies can impact which of the following? Dysphagia, jaundice, GI bleeding, or suspected bile leak? Very good. Thank you. The next question, please. Which of the following is the most important initial test for suspected cholelithiasis? Abdominal CT, ERCP, MRCP, or transabdominal ultrasound? Very good. Ultrasound is the most appropriate test. Very sensitive. Very specific. HIDISCAN is most useful in the evaluation of which of the following conditions? Post cholecystectomy bile leak, chronic abdominal pain, ascending cholangitis, or acute pancreatitis? Okay. As I mentioned before, one of the most useful, best uses for HIDISCAN is an evaluation for a post cholecystectomy bile leak. And with that, I will sign off and hand the floor back to Dr. Call.

imaging in gastroenterology

interpretation of imaging studies

transabdominal ultrasound

CT scans

MRIs

HIDA scans

abnormal imaging findings